chore: add a diagram to README.md (#13527)

README.md

@@ -100,6 +100,8 @@ For **Kubernetes deployments**, please refer to [Kubernetes with Helm](https://d
 
 RisingWave specializes in providing **incrementally updated, consistent materialized views** — a persistent data structure that represents the results of stream processing. RisingWave significantly reduces the complexity of building stream processing applications by allowing developers to express intricate stream processing logic through cascaded materialized views. Furthermore, it allows users to persist data directly within the system, eliminating the need to deliver results to external databases for storage and query serving.
 
+![Real-time Data Pipelines without or with RisingWave](https://github.com/risingwavelabs/risingwave/assets/100685635/414afbb7-5187-410f-9ba4-9a640c8c6306)
+
 Compared to existing stream processing systems like [Apache Flink](https://flink.apache.org/), [Apache Spark Streaming](https://spark.apache.org/docs/latest/streaming-programming-guide.html), and [ksqlDB](https://ksqldb.io/), RisingWave stands out in two primary dimensions: **Ease-of-use** and **cost efficiency**, thanks to its **[PostgreSQL](https://www.postgresql.org/)-style interaction experience** and  **[Snowflake](https://snowflake.com/)-like architectural design** (i.e., decoupled storage and compute).
 
 ### Ease-of-use